WO2003035778A2 - Thermally curable binding agents - Google Patents

Abstract

Thermally curable binding agents based on an aqueous polymer dispersion, containing an emulsion polymer (EP), a polymer which consists of at least 5 wt. % ethylenically unsaturated monocarboxylic acid, dicarboxylic acid or dicarboxylic acid anhydride (acid polymer SP) and monofunctional or multifunctional epoxy compounds as curing agents. The monofunctional or multifunctional epoxy compound is, preferably, introduced into the aqueous polymer dispersion in a liquid state. The thermally curable binding agent can contain a polymol or an alkanolamine, in addition to the epoxy compound, as curing agents.

Description

 Thermally curable binder

description

The present invention relates to a thermally curable binder based on an aqueous polymer dispersion containing

an emulsion polymer (EP for short), - a polymer which is composed of at least 5% by weight of an ethylenically unsaturated monocarboxylic acid, dicarboxylic acid or dicarboxylic acid anhydride (acid polymer SP for short) and mono- or multifunctional epoxy compounds as hardeners.

Furthermore, the present invention relates to a method for producing the thermally curable binders based on an aqueous polymer dispersion and their use as binders for moldings or nonwovens made of fibrous or granular materials.

Thermally curable binders made of polycarboxylic acids and polyols or alkanolamines are e.g. known from EP-A 445578, EP-A 583086, EP-A 882074, EP-A 882093 or DE-A 19949592.

In EP-A 882074 and DE-A 19949592, i.a. Alkoxysilanes mentioned as possible additives and hardeners for such binders. As further additives and hardeners for binders made of polycarboxylic acids and polyols, EP-A 445578 et al. multivalent amines disclosed.

EP-A 576 128 describes adhesive compositions which contain an acid-rich polymer component and an acid-poor polymer component. The acidic polymer component is based on a monomeric mixture of 40 to 95% of an alkyl acrylate or methacrylate and 5 to 60% of an ethylenically unsaturated acid, such as acrylic acid or methacrylic acid. The low-acid polymer component is based on a monomer mixture of 90 to 100% of an alkyl acrylate or alkyl methacrylate and 0 to 10% of an ethylenically unsaturated acid. The composition is prepared by aqueous emulsion polymerization, the acid-rich polymer component being polymerized in the presence of the low-acid polymer component or vice versa. The pH of the composition is adjusted to the desired value by adding ammonium hydroxide or sodium hydroxide. The composition is a pressure sensitive adhesive, lamination adhesive, Adhesive for textile fabrics, tiles and packaging and usable as wood glue.

Compared to the previously known thermally curable binders, it was the object of the present invention to provide improved thermally curable binders which, inter alia, are suitable for significantly increasing the strength of the moldings obtained therefrom and which are distinguished by a significantly reduced water absorption and solvent absorption and by a significantly reduced washout loss. At the same time, the binders according to the invention should be obtainable by a process which is as simple and economical as possible and should have a curing temperature which is as low as possible.

Accordingly, a thermally curable binder based on an aqueous polymer dispersion has been found to contain

- An emulsion polymer (EP for short), a polymer which is composed of at least 5% by weight of an ethylenically unsaturated monocarboxylic acid, dicarboxylic acid or dicarboxylic acid anhydride (acid polymer SP for short) and mono- or multifunctional epoxy compounds as hardeners.

Furthermore, a process for producing the thermally curable binders according to the invention and their use as binders for moldings or nonwovens made from fibrous or granular materials has also been found.

The emulsion polymer (EP) preferably consists of at least 40% by weight, more preferably at least 60% by weight, very particularly preferably at least 80% by weight of so-called main monomers.

The main monomers are selected from

C ₁ -C ₂ -alkyl (meth) acrylates, vinyl esters of carboxylic acids containing up to 20 C atoms, vinyl aromatics with up to 20 C atoms, ethylenically unsaturated nitriles, vinyl halides, vinyl ethers of alcohols containing 1 to 10 C atoms, aliphatic Hydrocarbons with 2 to 8 carbon atoms and 1 or 2 double bonds or mixtures of these monomers.

To mention are z. B. (Meth) acrylic acid alkyl ester with a -C-Cιo-alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate. Mixtures of the (meth) acrylic acid alkyl esters are also particularly suitable.

Vinyl esters of carboxylic acids with 1 to 20 carbon atoms are e.g. B. vinyl laurate, stearate, vinyl propionate, vinyl versatic acid and vinyl acetate.

Suitable vinyl aromatic compounds are vinyl toluene, α- and p-methylstyrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene and preferably styrene. Examples of nitriles are acrylonitrile and methacrylonitrile.

The vinyl halides are chlorine, fluorine or bromine-substituted ethylenically unsaturated compounds, preferably vinyl chloride and vinylidene chloride.

Examples of vinyl ethers include B. vinyl methyl ether or vinyl isobutyl ether. Vinyl ethers of alcohols containing 1 to 4 carbon atoms are preferred.

As hydrocarbons with 2 to 8 carbon atoms and two olefinic double bonds, butadiene, isoprene and chloroprene may be mentioned, with a double bond e.g. Ethylene or propylene.

The main monomers are the C ₁ -C 8 -alkyl acrylates and methacrylates, in particular the C 1 -C 6 -alkyl acrylates and methacrylates. Mixtures of Cχ-Cιo-alkyl acrylates or Cι-Cιo-alkyl methacrylates with vinyl aromatics, especially styrene, are also preferably considered.

Methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl acrylate, n-hexyl acrylate, octyl acrylate and 2-ethylhexyl acrylate, styrene and mixtures of these monomers are very particularly preferred.

In addition to the main monomers, the free-radically polymerized polymer may contain further monomers, e.g. B. monomers with carboxylic acid, sulfonic acid or phosphonic acid groups. Carboxylic acid groups are preferred. May be mentioned for. As acrylic acid, methacrylic acid, itaconic acid, maleic acid or fumaric acid.

Further monomers are, for example, also monomers containing hydroxyl groups, in particular C 1 -C 8 -hydroxyalkyl (meth) acrylates, such as, for example, hydroxyethyl acrylate, and (meth) acrylamides. Phenyloxyethyl glycol mono- (meth) acrylate, glycidyl acrylate, glycidyl methacrylate, amino (meth) acrylates such as 2-aminoethyl (meth) crylate may also be mentioned as further monomers.

Crosslinking monomers may also be mentioned as further monomers.

Monomers with hydrolyzable Si groups may also be mentioned.

The proportion of monomers with carboxylic acid groups or carboxylic anhydride groups is generally less than 10% by weight, in particular less than 5% by weight, based on EP.

EP is produced by emulsion polymerization.

In emulsion polymerization, ionic and / or nonionic emulsifiers and / or protective colloids or stabilizers can be used as surface-active compounds.

A detailed description of suitable protective colloids can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular Substances, Georg-Thieme-Verlag, Stuttgart, 1961, pp. 411 to 420. Both anionic, cationic and nonionic emulsifiers. Preferably, only accompanying emulsifiers are used as accompanying surface-active substances, the molecular weights of which, in contrast to the protective colloids, are usually below 2000 g / mol. Of course, if mixtures of surface-active substances are used, the individual components must be compatible with one another, which can be checked with a few preliminary tests if in doubt. Anionic and nonionic emulsifiers are preferably used as surface-active substances. Common accompanying emulsifiers are e.g. B. ethoxylated fatty alcohols (EO grade: 3 to 50, alkyl radical: C ₈ - to C _3ß ), ethoxylated mono-, di- and tri-alkylphenols (EO degree: 3 to 50, alkyl radical: C ₄ - to C ₉ ), Alkali metal salts of dialkyl esters of sulfosuccinic acid and alkali and ammonium salts of alkyl sulfates (alkyl radical: C _& - to Cχ ₂ ), of ethoxylated alkanols (EO grade: 4 to 30, alkyl radical: C ₁₂ - to C _i8 ), of ethoxylated alkylphenols (EO grade: 3 to 50, alkyl radical: C ₄ - to C ₉ ), of alkyl sulfonic acids (alkyl radical: Cχ ₂ - to Ciβ) and of alkylarylsulfonic acids (alkyl radical: Cg to Cis) •

worin R⁵ und R⁶ Wasserstoff oder C₄- bis Cι₄-Alkyl bedeuten und nicht gleichzeitig Wasserstoff sind, und X und Y Alkalimetall- ionen und/oder Ammoniumionen sein können. Vorzugsweise bedeuten R⁵, R⁶ lineare oder verzweigte Alkylreste mit 6 bis 18 C-Atomen oder Wasserstoff und insbesondere mit 6, 12 und 16 C-Atomen, wobei R⁵ und R⁶ nicht beide gleichzeitig Wasserstoff sind. X und Y sind bevorzugt Natrium, Kalium oder Ammoniumionen, wobei Natrium besonders bevorzugt ist. Besonders vorteilhaft sind Verbindungen I in denen X und Y Natrium, R⁵ ein verzweigter Alkylrest mit 12 C-Atomen und R⁶ Wasserstoff oder R⁵ ist. Häufig werden technische Gemische verwendet, die einen Anteil von 50 bis 90 Gew.-% des monoalkylierten Produktes aufweisen, beispielsweise Dowfax® 2A1 (Warenzeichen der Dow Chemical Company) .Other suitable emulsifiers are compounds of the general formula I.

wherein R ⁵ and R ^{6 are} hydrogen or C ₄ - to -C ₄ alkyl and are not simultaneously hydrogen, and X and Y can be alkali metal ions and / or ammonium ions. R ⁵ , R ^{6 are} preferably linear or branched alkyl radicals having 6 to 18 carbon atoms or hydrogen and in particular having 6, 12 and 16 carbon atoms, where R ⁵ and R ^{6 are} not both hydrogen at the same time. X and Y are preferably sodium, potassium or ammonium ions, with sodium being particularly preferred. Compounds I in which X and Y are sodium, R ^{5 is} a branched alkyl radical having 12 C atoms and R ^{6 is} hydrogen or R ⁵ are particularly advantageous. Technical mixtures are frequently used which have a proportion of 50 to 90% by weight of the monoalkylated product, for example Dowfax® 2A1 (trademark of the Dow Chemical Company).

Suitable emulsifiers can also be found in Houben-Weyl, Methods of Organic Chemistry, Volume 14/1, Macromolecular Substances, Georg Thieme Verlag, Stuttgart, 1961, pages 192 to 208.

Trade names of emulsifiers are e.g. B. Dowfax®2 AI, E ulan® NP 50, Dextrol® OC 50, Emulsifier 825, Emulsifier 825 S, Emulan® OG, Texapon®NSO, Nekanil® 904 S, Lumiten® I-RA, Lu iten E 3065, Dis - ponil FES 77, Lutensol AT 18, Steinapol VSL, Emulphor NPS 25.

The surface-active substance is usually used in amounts of 0.1 to 10% by weight, based on the monomers to be polymerized.

Water-soluble initiators for emulsion polymerization are e.g. Ammonium and alkali metal salts of peroxidic sulfuric acid, e.g. Sodium peroxodisulfate, hydrogen peroxide or organic peroxides, e.g. tert-butyl hydroperoxide.

So-called reduction-oxidation (red-ox) initiator systems are also suitable.

The redox initiator systems consist of at least one mostly inorganic reducing agent and one inorganic or organic oxidizing agent. The oxidation component is, for example, the initiators for emulsion polymerization already mentioned above.

The reduction component is e.g. alkali metal salts of sulfurous acid, e.g. Sodium sulfite, sodium bisulfite, alkali metal salts of disulfuric acid such as sodium disulfite, bisulfite addition compounds of aliphatic aldehydes and ketones, such as acetone bisulfite or reducing agents such as hydroxymethanesulfinic acid and its salts, or ascorbic acid. The 10 Red-Ox initiator systems can be more soluble when used

Metal compounds whose metallic component can occur in several valence levels can be used.

Common red-ox initiator systems are e.g. Ascorbic acid / iron (II) sulfate / sodium peroxydisulfate, tert-butyl hydroperoxide / sodium disulfite, tert-butyl hydroperoxide / Na hydroxymethanesulfinic acid. The individual components, e.g. the reduction component, can also be mixtures e.g. a mixture of the sodium salt of hydroxymethanesulfinic acid and sodium disulfite. 20

The compounds mentioned are mostly used in the form of aqueous solutions, the lower concentration being determined by the amount of water acceptable in the dispersion and the upper concentration being determined by the solubility of the compound in question in water. The concentration is generally 0.1 to 30% by weight, preferably 0.5 to 20% by weight, particularly preferably 1.0 to 10% by weight, based on the solution.

The amount of initiators is generally 0.1 to 30 10% by weight, preferably 0.5 to 5% by weight, based on the monomers to be polymerized. Several different initiators can also be used in emulsion polymerization.

Regulators can be used in the polymerization, e.g. in 35 amounts of 0 to 0.8 parts by weight, based on 100 parts by weight of the monomers to be polymerized, by means of which the molecular weight is reduced. Suitable are e.g. Compounds with a thiol group such as tert. -Butyl mercaptan, thioglycolic acid, ethyl hexyl acrylate, mercaptoethanol, mercaptopropyltrimethoxysilane or tert-dode-0 cyl ercapta.

The emulsion polymerization is usually carried out at 20 to 130, preferably 50 to 90 ° C. The polymerization medium can consist only of water, as well as mixtures of water and thus 5 miscible liquids such as methanol. Preferably only water is used. The emulsion polymerization can be carried out either as a batch process or in the form of a feed process, including borrowed step or gradient mode. Preference is given to the feed process, in which part of the polymerization batch is initially charged, heated to the polymerization temperature, polymerized and then the rest of the polymerization batch, usually via a plurality of spatially separate feeds, one or more of which contain the monomers in pure or in emulsified form , continuously, stepwise or by superimposing a concentration gradient while maintaining the polymerization of the polymerization zone. In the polymerization, for example, can also improve

Setting the particle size a polymer seed can be submitted.

The manner in which the initiator is added to the polymerization vessel in the course of the free radical aqueous emulsion polymerization is known to the person skilled in the art. It can either be completely introduced into the polymerization vessel or used continuously or in stages in the course of the free-radical aqueous emulsion polymerization, depending on its consumption. In detail, this depends on the chemical nature of the initiator system as well as on the polymerization temperature. A portion is preferably introduced and the remainder is fed to the polymerization zone in accordance with the consumption.

To remove the residual monomers, usually after the end of the actual emulsion polymerization, i.e. after a conversion of the monomers of at least 95%, initiator added.

The individual components can be added to the reactor in the feed process from above, from the side or from below through the reactor floor.

In emulsion polymerization, aqueous dispersions of the polymer are generally obtained with solids contents of from 15 to 75% by weight, preferably from 40 to 75% by weight.

For a high space / time yield of the reactor, dispersions with the highest possible solids content are preferred. In order to be able to reach solids contents> 60% by weight, one should set a bimodal or polymodal particle size, since otherwise the viscosity becomes too high and the dispersion can no longer be handled. A new generation of particles can be generated, for example, by adding seeds (EP-A 81083), by adding excess amounts of emulsifier or by adding mini-emulsions. Another advantage associated with the low viscosity at high solids content is the improved coating behavior at high solids contents. The generation of a new / new generation of particles can occur at any time respectively. It depends on the particle size distribution desired for a low viscosity.

The polymer thus produced is preferably used in the form of its aqueous dispersion.

The glass transition temperature of the polymeric binder or of the emulsion polymer is preferably -60 to + 150 ° C, particularly preferably -50 to + 140 ° C and very particularly preferably -4 ° to + 120 ° C.

The glass transition temperature can be determined by conventional methods such as differential thermal analysis or differential scanning calorimetry (see e.g. ASTM 3418/82, so-called "midpoint temperature").

In addition to the emulsion polymer (EP), the aqueous polymer dispersion contains mono- or multifunctional epoxy compounds as hardeners. In particular, di- or trifunctional epoxy compounds are preferably used, for example the corresponding glycidyl ethers. Particularly suitable epoxy compounds include Bisphenol A diglycidyl ether of the general formula (II)

(II)

where n is 0 to 15.

The corresponding bisphenol A diglycidyl ether derivative with n = 0 is sold, for example, as a commercial product under the name Epicote® 828 by Shell.

Other particularly suitable epoxy compounds include Butanediol diglycidyl ether, pentaerythritol triglycidyl ether, neopentylglycoldiglycidether or hexanediol diglycidether. Water dispersible epoxy compounds can also be used.

In general, epoxy compounds include aromatic glycidyl compounds such as the bisphenols A of the formula (II) or their bromine derivatives, furthermore phenol novolak glycidyl ether or cresol novolak glycidyl ether, bisphenol F diglycidyl ether,

Glyoxal tetraphenol tetraglycidyl ether, N, N-diglycidyl aniline, p-aminophenol triglycid or 'but

4,4'-diaminodiphenylmethane tetraglycid can be used.

Also suitable as epoxy compounds include cycloaliphatic glycidyl compounds such as tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester or hydrogenated bisphenol A diglycidyl ether or heterocyclic glycidyl compounds such as triglycidyl isocyanurate and triglycidyl bis-hydantoi.

10

In addition, cycloaliphatic epoxy resins such as 3, 4-epoxycyclohexane-3'-epoxycyclohexylmethyl ester, bis- (3, 4-epoxycyclohexylmethylU-adipate or 3- (3 ', 4'-epoxycyclohexyl ) -2, 4-dioxa-

15 spiro [5, 5] -8, -epoxyundecan and aliphatic epoxy resins such as butane-l, 4-diol diglycidyl ether or polypropylene glycol 425 diglycidyl ether can be used.

The epoxy compounds used according to the invention can be stirred into the aqueous polymer dispersion both before and during the polymerization of the monomers forming the emulsion polymer and also after this polymerization has ended. The epoxy compounds can be stirred in at temperatures from 10 to 100 ° C., in particular at temperatures from 10 to 25 50 ° C. They are preferably used as hardeners in the liquid state.

The amount of mono- or multifunctional epoxy compounds in the solids content of the binder according to the invention, i.e. 30 based on 100 parts by weight of the sum of the emulsion polymer and the acid polymer (EP and SP) is preferably 0.1 to 50 parts by weight, in particular 0.2 to 30 parts by weight, particularly preferably 0.5 to 25 parts by weight.

35 Both single and mixtures of different mono- or multifunctional epoxy compounds can be used as hardeners. Such epoxy compounds are commercially available.

The aqueous polymer dispersion also contains the acid polymer SP defined at the beginning.

SP is a radically polymerized polymer which is composed of 5 to 100% by weight, preferably 20 to 100% by weight, particularly preferably 40 to 100% by weight, of an ethylenically unsaturated acid or 45 an ethylenically unsaturated acid anhydride. Acrylic acid or methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride may be mentioned in particular.

Most preferably SP contains acid anhydrides e.g. Maleic anhydride or dicarboxylic acids which can form anhydrides e.g. Maleic acid.

In particular, the polymers SP contain 5 to 50% by weight, preferably 10 to 40% by weight, of the last-mentioned dicarboxylic acids or acid anhydrides. The rest of the ethylenically unsaturated

Compounds from which the polymer is built up are preferably acrylic acid or methacrylic acid.

The acids can in principle also be used as salts, e.g. Alkali or ammonium salts are present and used. Salts of amines are also suitable.

In addition, the polymer can e.g. also contain the following monomers as structural components:

Cj-Cβ-alkyl (meth) acrylates, vinyl esters, vinyl ethers, olefins, vinyl halides, unsaturated nitriles etc.

The aqueous polymer dispersion can also contain a polyol as crosslinking agent for the polymer SP.

These are preferably low molecular weight compounds with a molecular weight below 2000 g / mol, in particular below 1000 g / mol.

Preference is given to 2- to 5-valent polyols, such as glycerol, trimethylolpropane, etc.

Alkanolamines are particularly preferred. Diethanolamine and triethanola are particularly mentioned in. Further preferred alkanolamines include known from EP-A 902796, the disclosure content in this regard is part of the present description of the invention.

Polymers SP as described in EP-A 882074 are particularly suitable.

SP and polyol crosslinker are preferably used in such a ratio to one another that the molar ratio of carboxyl groups and the hydroxyl groups is preferably 20: 1 to 1: 1 8: 1 to 5: 1 and particularly preferably 5: 1 to 1.7: 1 (anhydride groups are calculated here as 2 carboxyl groups).

The acid polymer and the polyol can be added to the aqueous dispersion at any time.

The aqueous polymer dispersion may contain reaction accelerators containing phosphorus; however, it preferably contains no such compounds.

In a particular embodiment, the emulsion polymer is prepared in the presence of at least a portion of the acid polymer SP. In this case, SP is preferred

50 to 99.5% by weight of at least one ethylenically unsaturated mono-, dicarboxylic acid or dicarboxylic acid anhydride,

0.5 to 50% by weight of at least one ethylenically unsaturated compound which is selected from the esters of ethylenically unsaturated monocarboxylic acids and the half-esters and diesters of ethylenically unsaturated dicarboxylic acids with an amine having at least one hydroxyl group,

up to 20% by weight of at least one further monomer.

The emulsion polymerization is particularly preferably carried out in the presence of at least 30% by weight, in particular at least 50% by weight, very particularly preferably 100% by weight, of the total amount of SP.

The polymer SP contains 50 to 99.5% by weight, preferably 70 to 99% by weight, of built-in structural elements which are derived from at least one ethylenically unsaturated mono- or dicarboxylic acid. If desired, these acids can also be partially or completely in the form of a salt in the polymer. The acid form is preferred.

SP is preferably soluble in water to more than 10 g / l (at 25 ° C.).

Preferred carboxylic acids are C ₃ - to Cio-monocarboxylic acids and C ₄ - to C _ß -dicarboxylic acids, especially acrylic acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, 2-methylmaleic acid and / or itaconic acid. Acrylic acid, methacrylic acid, maleic acid and mixtures thereof are particularly preferred. In the production of the polymer SP, it is of course also possible to replace the acids or together with the acids, their anhydrides, such as maleic acid. reanhydride, acrylic or methacrylic anhydride can be used.

The polymer SP also contains 0.5 to 50% by weight, preferably 1 to 30% by weight, of at least one ethylenically unsaturated compound which is selected from the esters of ethylenically unsaturated monocarboxylic acids and the half-esters and diesters of ethylenically unsaturated dicarboxylic acids with at least one hydroxyl group-containing amine, in copolymerized form.

The polymer SP is preferably in the form of a comb polymer with covalently bonded amine side chains.

Monocarboxylic acids suitable for the esters are the aforementioned C ₃ - to Cio-monocarboxylic acids, in particular acrylic acid, methacrylic acid, crotonic acid, and mixtures thereof.

Dicarboxylic acids suitable for the half esters and diesters are the aforementioned C ₄ - to C ₆ -dicarboxylic acids, in particular fumaric acid, maleic acid, 2-methyl maleic acid, itaconic acid, and mixtures thereof.

The amine having at least one hydroxyl group is preferably selected from secondary and tertiary amines which have at least one C ₆ -C ₂₂ -alkyl, C ₆ -C ₂₂ -alkenyl, aryl-C ₆ -C bis

C ₂₂ ^_ alkyl or aryl-Cε to C ₂₂ alkenyl radical, where the alkenyl group 1, 2 or 3 may not have adjacent double bonds.

The amine is preferably hydroxyalkylated and / or alkoxylated. Alkoxylated amines preferably have one or two alkylene oxide radicals with terminal hydroxyl groups. The alkylene oxide radicals preferably each have 1 to 100, preferably 1 to 50, identical or different alkylene oxide units, randomly distributed or in the form of blocks. Preferred alkylene oxides are ethylene oxide, propylene oxide and / or butylene oxide. Ethylene oxide is particularly preferred.

The polymer SP preferably contains an unsaturated compound based on an amine component, which contains at least one amine of the general formula

R ^c NR ^a R ^b contains 11, while R ^c is C ₆ - to C ₂ alkyl, C ₆ - to C ₂₂ alkenyl, aryl-C ₆ -C ₂₂ alkyl or aryl-C ₆ -C ₂₂ alkenyl, wherein the alkenyl group 1, 2 or 3 may not have adjacent double bonds,

R ^a for hydroxy-Ci-Cö-alkyl or a radical of the formula (III)

- (CH ₂ CH ₂ θ) _x (CH ₂ CH (CH ₃ ) 0) _y -H (III)

in formula (III) the sequence of the alkylene oxide units is arbitrary and x and y independently of one another represent an integer from 0 to 100, preferably 0 to 50, the sum of x and y being> 1,

R ^b for hydrogen, C - to C ₂₂ -alkyl, hydroxy-Cx-Cε-alkyl, C ₆ - to C ₂₂ -alkenyl, aryl-C6-C ₂ -alkyl, aryl-C ₆ -C ₂₂ -alkenyl or C ₅ - to C ₈ -cycloalkyl, where the alkenyl radical may have 1, 2 or 3 non-adjacent double bonds, or R ^{b represents} a radical of the formula (IV)

(CH ₂ CH ₂ 0) _v (CH ₂ CH (CH ₃ ) 0) _w -H (IV)

in the formula (IV) the sequence of the alkylene oxide units is arbitrary and v and w independently of one another represent an integer from 0 to 100, preferably 0 to 50.

R ^{c is} preferably CQ to C ₂₀ alkyl or C ₈ to C ₂ o-alkenyl, where the alkenyl radical can have 1, 2 or 3 non-adjacent double bonds. R ^c is preferably the hydrocarbon radical of a saturated or mono- or polyunsaturated fatty acid. Preferred radicals R ^c are e.g. B. n-octyl, ethylhexyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, palmityl, margaminyl, stearyl, pal itoleinyl, oleyl and linolyl.

The amine component is particularly preferably an alkoxylated fatty amine or an alkoxylated fatty amine mixture. The ethoxylates are particularly preferred. In particular, alkoxylates of amines based on naturally occurring fatty acids are used, such as. B. tallow fatty amines which contain predominantly saturated and unsaturated C ₁₄ -, C ₆ - and Cis-alkyla ine or cocosamines which contain saturated, mono- and di-unsaturated C ₆ ~ C ₂₂ -, preferably C ₂ -Ci ₄ alkylamines , Amine mixtures suitable for alkoxylation are e.g. For example, various Armenen® brands from Akzo or Noram® brands from Ceca. Suitable, commercially available alkoxylated amines are e.g. B. the Noramox® brands from Ceca, preferably ethoxylated oleylamines, such as Noramox® 05 (5 EO units), and the products from BASF Aktiengesellschaft sold under the Lutensol®FA brand.

The copolymerization of the aforementioned esters, half esters and diesters generally brings about a pronounced stabilization of a polymer dispersion which is prepared in the presence of SP. The binders according to the invention reliably maintain their colloidal stability of the latex particles when diluted with water or dilute electrolytes or surfactant solutions.

The esterification for the preparation of the esters, half esters and diesters described above is carried out by customary processes known to the person skilled in the art. To prepare esters of unsaturated monocarboxylic acids, the free acids or suitable derivatives, such as anhydrides, halides, e.g. As chlorides, and (Ci to C ₄ ) alkyl esters can be used. Half-esters of unsaturated dicarboxylic acids are preferably prepared starting from the corresponding dicarboxylic acid anhydrides. The reaction is preferably carried out in the presence of a catalyst, such as. B. a dialkyl titanate or an acid such as sulfuric acid, toluenesulfonic acid or methanesulfonic acid. The reaction generally takes place at reaction temperatures of 60 to 200 ° C. According to a suitable embodiment, the reaction takes place in the presence of an inert gas, such as nitrogen. Water formed in the reaction can be removed from the reaction mixture by suitable measures, such as distillation. If desired, the reaction can be carried out in the presence of customary polymerization inhibitors. The esterification reaction can be carried out essentially completely or only up to a partial conversion. If desired, one of the ester components, preferably the hydroxyl-containing amine, can be used in excess. The proportion of ester formation can be determined using infrared spectroscopy.

According to a preferred embodiment, the preparation of the unsaturated esters, half esters or diesters and their further conversion to the polymers SP takes place without intermediate isolation of the esters and preferably in succession in the same reaction vessel.

A reaction product of a dicarboxylic anhydride, preferably maleic anhydride, and one of the hydroxyl-containing amines described above is preferably used to prepare the polymers SP. In addition to the constituents carboxylic acid and also esters, half esters and / or diesters, the polymer SP may also contain 0 to 20% by weight, preferably 0.1 to 10% by weight, of other monomers in copolymerized form. Usable monomers are the monomers mentioned in connection with the polymer 5 AI, vinyl aromatics such as styrene, olefins, for example ethylene, or (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth ) acrylate, 2-ethylhexyl (meth) crylate and mixtures thereof are particularly preferred.

10

The polymers SP are preferably prepared by radical polymerization in bulk or in solution. Suitable solvents for solvent polymerization are e.g. As water, water-miscible organic solvents such as alcohols

15 and ketones, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, acetone, methyl ethyl ketone etc., and mixtures thereof. Suitable polymerization initiators are, for example, peroxides, hydroperoxides, peroxodisulfates, percarbonates, peroxoesters, hydrogen peroxide and azo compounds, as described above for

20 the preparation of the polymer dispersions according to the invention are described in more detail. If desired, the polymers SP can be prepared separately and isolated and / or purified by customary processes. The polymers SP are preferred immediately before the polymer dispersions according to the invention are prepared

25 manufactured and used without intermediate insulation for dispersion polymerization.

The polymers SP can advantageously also be prepared by polymer-analogous reaction. For this purpose, a polymer containing 30 80 to 100 wt .-% of at least one ethylenically unsaturated

Contains mono- and / or dicarboxylic acid and 0 to 20 wt .-% of the aforementioned other polymers incorporated, are reacted with at least one hydroxyl-containing amine.

The weight ratio of polymer EP to polymer SP, on a solid basis, is preferably in the range from 7: 1 to 1: 7, in particular 3: 1 to 1: 3.

In addition to the polymers EP and SP and the epoxy compounds, the aqueous polymer dispersion can also contain 0 to 50% by weight, preferably 0.1 to 40% by weight, based on the polymer SP, of at least one surface-active, alkoxylated, preferably ethoxylated (EO ) or propoxylated (PO), alkylamines. Preferred alkylamines are the alkylamines of the formula R ^c NR ^a R ^b , as previously defined, which are also present in the polymer SP, alkyl alkyl of the formula ^ (EO / PO) _m

N - (EO / PO) _n

in which R represents an alkyl, alkenyl or alkylvinyl radical having at least 6 carbon atoms and m and n independently of one another are> 1, are particularly preferred. Preferred radicals R have 8 to 22 carbon atoms.

The alkoxylated alkylamines contained in the polymer SP and the additional alkylamine crosslinkers can be the same or different compounds.

Contain particularly preferred compositions of the polymer dispersions

, a) 70 to 30% by weight of polymer EP, b) 30 to 70% by weight of polymer SP and optionally c) 0 to 10% by weight of surface-active alkoxylated alkyla in, d) 0 to 20% by weight of polyol Crosslinker, e) 0 to 5% by weight of reaction accelerator (in particular none

Reaction accelerator), as well as

based on the total weight of a) to e), the above amount of mono- or multifunctional epoxy compounds.

In addition to the ingredients mentioned, customary additives can be added depending on the application. The polymer dispersion and the polymer dispersion containing further additives are also referred to below collectively as "composition".

The components optionally additionally contained in the composition are generally added after the end of the emulsion polymerization.

The compositions can furthermore contain customary additives, depending on the application. For example, they can contain bactericides or fungicides. In addition, they can contain water repellents to increase the water resistance of the treated substrates. Suitable water repellents are customary aqueous paraffin dispersions or silicones. The compositions may also contain wetting agents, thickeners, plasticizers, retention agents, pigments and fillers. Finally, the compositions can be conventional fire retardants, such as. B. contain aluminum silicates, aluminum hydroxides, borates and / or phosphates.

The compositions can also be used in combination with other binders, such as, for example, urea-formaldehyde resins, melamine-formaldehyde resins or phenol-formaldehyde resins.

The compositions are preferably formaldehyde free. Formaldehyde-free means that the compositions do not contain any significant amounts of formaldehyde and that no significant amounts of formaldehyde are released even when drying and / or curing. Generally the compositions contain <100 ppm formaldehyde. They enable the production of moldings with a short curing time and give the moldings excellent mechanical properties.

The compositions are essentially uncrosslinked before use and are therefore thermoplastic. If necessary, however, a low degree of pre-crosslinking of the polymer EP can be set, e.g. B. by using monomers with two or more polymerizable groups.

The polymer dispersion or composition can e.g. as a binder for fibrous and granular substrates, such as. B. wood chips, wood fibers, textile fibers, glass fibers, mineral fibers or natural fibers such as jute, flax, hemp or sisal, but also cork chips or sand can be used. After hardening, molded parts with high mechanical strength are obtained, which retain their dimensional stability even in a humid climate. Thermal curing is preferred. The curing temperatures are generally 80 to 250 ° C, preferably 100 to 200 ° C.

When heated, the water contained in the composition evaporates and the composition hardens. These processes can take place sequentially or simultaneously. In this context, hardening means the chemical change in the composition, e.g. B. the crosslinking by forming covalent bonds between the various components of the compositions, formation of ionic interactions and clusters, formation of hydrogen bridges. Furthermore, physical changes in the binder can take place during curing, such as. B. phase changes or phase inversions. An advantage of the thermally curable binder according to the invention is that it can be cured at comparatively low temperatures. The duration and temperature of warming influence the degree of curing. The quality of the crosslinking can be determined via the washout loss in water at room temperature (RT). The so-called gel content of the polymer is obtained. The gel content of polymer films after a 30 min. long crosslinking at 130 ° C. is at least 50%, preferably at least 70%. The degree of crosslinking caused by the epoxy can be determined, inter alia, by infrared spectroscopy.

The curing can also take place in two or more stages. So z. B. in a first step, the curing temperature and time are chosen so that only a low degree of curing is achieved and largely complete curing takes place in a second step. This second step can take place spatially and temporally separately from the first step. This makes it possible, for example, to use the thermally curable binders according to the invention for the production of semi-finished products impregnated with binders, which can be deformed and cured at another point.

Another object of the invention is the use of the thermally curable binders based on an aqueous polymer dispersion as binders for moldings and nonwovens made of fibrous or granular materials and subsequent curing.

Shaped bodies of this type preferably have a density of 0.2 to 1.4 g / cm 3 at 23 ° C.

In particular, plates and contoured moldings are suitable as moldings. Their thickness is generally at least 1 mm, preferably at least 2 mm, and their surface area is typically 200 to 200,000 cm ² . In particular, wood fiber and chipboard, cork boards, blocks and molds, insulation boards and rolls, z. B. from mineral and glass fibers, automotive interior parts, for. B. interior door panels, dashboards, hat racks, etc.

The amount by weight of the binder used is generally 0.5 to 40% by weight, preferably 1 to 30% by weight (solid binder), based on the substrate (fibers, chips or chips) from which the shaped body or the nonwoven is then made is formed.

The fibers, chips or chips can be coated directly with the binder or mixed with the aqueous binder. The viscosity of the aqueous binder is preferably from 10 to 4,000 mPas, preferably from 30 to 2,000 mPas (DIN 53019, rotational viscometer at 250 sec " ¹ ) set.

The mixture of fibers, chips and chips and the binder can e.g. B. pre-dried at temperatures of 10 to 150 ° C and then to the moldings, for. B. at temperatures of 80 to 250 ° C, preferably 100 to 200 ° C, and pressures of generally 2 to 1000 bar, preferably 10 to 750 bar, particularly preferably 200 to 500 bar to the moldings.

The binders are particularly suitable for the production of wood-based materials such as chipboard and wood fiber boards (cf. Ullmann's Encyclopedia of Industrial Chemistry, 4th edition 1976, volume 12, pp. 709-727), which are obtained by gluing split wood, such as. B. wood chips and wood fibers can be produced. The water resistance of wood-based materials can be increased by adding a commercially available aqueous paraffin dispersion or other hydrophobizing agent to the binder, or adding these hydrophobizing agents to the fibers, chips or chips beforehand or afterwards.

The production of chipboard is well known and is described for example in H.J. Deppe, K. Ernst Paperback of chipboard technology, 2nd edition, Verlag Leinfelden 1982, described.

Chips are preferably used whose average chip size is between 0.1 and 4 mm, in particular 0.2 and 2 mm, and which contain less than 6% by weight of water. However, it is also possible to use significantly coarser chips and those with a higher moisture content. The binder is applied to the wood chips as evenly as possible, the weight ratio of binder: wood chips preferably being 0.02: 1 to 0.3: 1. A uniform distribution can be achieved, for example, by spraying the binder in finely divided form onto the chips.

The glued wood chips are then spread into a layer with a surface that is as uniform as possible, the thickness of the layer depending on the desired thickness of the finished chipboard. The scattering layer is pressed to a plate at a temperature of, for example, 100 to 250 ° C., preferably 120 to 225 ° C., by using pressures of usually 10 to 750 bar. The pressing times required can vary within a wide range and are generally between 15 seconds and 30 minutes. The wood fibers of suitable quality required for the production of medium-density wood fiber boards (MDF) from the binders can be produced from bark-free wood chips by grinding in special mills or so-called refiners at temperatures of approx. 180 ° C.

For gluing, the wood fibers are generally whirled up with an air stream and the binder is injected into the fiber stream thus produced (“blow-line” process). The ratio of wood fibers to binder, based on the dry content or solids content, is usually 40: 1 to 2: 1, preferably 20: 1 to 4: 1. The glued fibers are in the fiber stream at temperatures of e.g. B. 130 to 180 ° C dried, spread into a nonwoven fabric and pressed at pressures of 10 to 50 bar to plates or moldings.

, The glued wood fibers can also, such as. B. described in DE-A 2 417 243, processed into a transportable fiber mat. This semi-finished product can then in a second, temporally and spatially separate step to plates or moldings, such as. B. Door linings of motor vehicles are processed.

Other natural fibers such as sisal, jute, hemp, flax, coconut fibers, banana fibers and other natural fibers can also be processed with the binders into sheets and molded parts. The natural fiber materials can also be mixed with plastic fibers, e.g. B. polypropylene, polyethylene, polyester, polyamides or polyacrylonitrile can be used. These plastic fibers can also act as cobinders in addition to the binder according to the invention. The proportion of plastic fibers is preferably less than 50% by weight, in particular less than 30% by weight and very particularly preferably less than 10% by weight, based on all chips, chips or fibers. The fibers can be processed according to the method practiced with wood fiber boards. However, preformed natural fiber mats can also be impregnated with the binders, if appropriate with the addition of a wetting aid. The impregnated mats are then z. B. at temperatures between 100 and 250 ° C and pressures between 10 and 100 bar to form plates or molded parts.

When pressed, the substrates impregnated with the binders preferably have a residual moisture content of 3 to 20% by weight, based on the substrate to be bound. The moldings obtained have a low water absorption, a low swelling in thickness after storage in water, good strength and are free of formaldehyde.

In addition, the compositions can be used as binders for coating and impregnating compositions for boards made from organic and / or inorganic fibers, non-fibrous mineral fillers and starch and / or aqueous polymer dispersions. The coating and impregnation compounds give the panels a high flexural modulus. The manufacture of such plates is known.

Such panels are usually used as soundproofing panels. The thickness of the plates is usually in the range from about 5 to 30 mm, preferably in the range from 10 to 25 mm. The edge length of the square or rectangular plates is usually in the range from 200 to 2,000 mm.

Furthermore, the compositions can contain auxiliaries customary in coating and impregnation technology. Examples of these are finely divided inert fillers, such as aluminum silicates, quartz, precipitated or pyrogenic silica, light and heavy spar, talc, dolomite or calcium carbonate; coloring pigments such as titanium white, zinc white, iron oxide black etc., show inhibitors such as modified dimethylpolysiloxanes, and adhesion promoters and preservatives.

The components of the composition are generally contained in the coating ace in an amount of 1 to 65% by weight. The proportion of inert fillers is generally 0 to 85% by weight, the water content is at least 10% by weight .-%.

The compositions are used in the customary manner by application to a substrate, for example by spraying, rolling, pouring or impregnation. The amounts applied, based on the dry content of the composition, are generally from 2 to 100 g / m ² .

The amounts of additives to be used are known to the person skilled in the art and depend in individual cases on the desired properties and the intended use.

The compositions are also useful as binders for insulating materials made from inorganic fibers, such as mineral fibers and glass fibers. Such insulation materials are produced industrially by spinning melts of the corresponding mineral raw materials, see US-A 2,550,465, US-A 2,604,427, US-A 2,830,648, EP-A 354 913 and EP-A 567 480. The composition is then sprayed onto the freshly produced, still hot inorganic fibers. The water then largely evaporates and the composition remains essentially uncured as a viscose mass adhering to the fibers. An endless, binder-containing fiber mat produced in this way is transported further by suitable conveyor belts through a curing oven. There the mat hardens to a rigid matrix at temperatures in the range of approx. 100 to 200 ° C. After curing, the insulation mats are assembled in a suitable manner.

The majority of the mineral or glass fibers used in the insulation materials have a diameter in the range from 0.5 to 20 μm and a length in the range from 0.5 to 10 cm.

The binders according to the invention can i.a. used in the manufacture of filter papers for air and oil filters. They can also be used as components of decorative papers.

The compositions are also suitable as binders for nonwoven fabrics.

As nonwovens such. B. nonwovens made of cellulose, cellulose acetate, esters and ethers of cellulose, cotton, hemp, animal fibers such as wool or hair and in particular nonwovens made of synthetic or inorganic fibers, eg. B. aramid, carbon, polyacrylonitrile, polyester, mineral, PVC or glass fibers.

In the case of use as a binder for nonwoven fabrics, the compositions can e.g. B. contain the following additives: silicates, silicones, boron-containing compounds, lubricants, wetting agents.

Glass fiber nonwovens are preferred. The unbound non-woven fabrics (raw fiber non-woven fabrics), in particular made of glass fibers, are bound by the binder according to the invention, i. H. solidified.

For this purpose, the binder is preferably in the weight ratio fiber / binder (solid) from 10: 1 to 1: 1, particularly preferably from 6: 1 to 3: 1 on the raw fiber fleece z. B. applied by coating, impregnation, watering.

The binder is preferably used in the form of a dilute aqueous preparation with 95 to 40% by weight of water. After the binder has been applied to the raw fiber fleece, drying and crosslinking are generally carried out, preferably at 100 to 400, in particular 130 to 280 ° C., very particularly preferably 130 to 230 ° C. over a period of preferably 10 seconds to 10 minutes, in particular from 10 seconds to 3 minutes.

The bonded nonwoven fabric obtained has a high strength in the dry and wet state. The binders according to the invention in particular allow short drying times and also low drying temperatures. They can also be dried into semi-finished products, which allow later processing.

The bonded nonwovens, in particular glass fiber nonwovens, are suitable for use as or in roofing membranes, as carrier materials for wallpapers or as inliners or carrier material for floor coverings, for. B. PVC.

When used as roofing membranes, the bonded fiber nonwovens are generally coated with bitumen.

Foamed sheets or moldings can also be produced from the aqueous compositions. For this purpose, the water contained in the composition is first removed at temperatures from <100 ° C. to a content of <20% by weight. The viscous composition thus obtained is then foamed at temperatures> 100 ° C., preferably at 120 to 300 ° C. As a blowing agent z. B. serve the residual water still contained in the mixture and / or the gaseous reaction products formed in the curing reaction. However, commercial blowing agents can also be added. The resulting cross-linked polymer foams can be used, for example, for thermal insulation and sound insulation.

With the compositions, so-called laminates, e.g. B. for decorative applications. In a second step, these are laminated onto the substrate to be coated under the action of heat and pressure, the conditions being selected so that the binder cures.

The compositions can furthermore be used for the production of abrasive paper and abrasive articles by the production processes usually carried out with phenol resin as a binder. In the production of abrasive papers, a layer of the inventive ß binder applied as a base binder (advantageously 10 g / m ² ). The desired amount of abrasive grain, e.g. B. silicon carbide, corundum, etc., interspersed. After intermediate drying, a cover binder layer is applied (eg 5 g / m ² ). The paper coated in this way is then tempered for 5 minutes at 170 ° C. for curing.

The hardness and flexibility of the composition can be adjusted to the desired level via the composition of the polymer SP.

The compositions are also suitable as formaldehyde-free sand binders for the production of casting molds and casting cores for metal casting by the customary thermal hardening processes (E. Flemming, W. Tilch, Formstoffe und Formverfahren, Dt. Verlag für Grundstoffindustrie, Stuttgart, 1993).

They are also suitable as binders for mold insulation panels.

The thermally curable binders according to the invention based on an aqueous polymer dispersion are distinguished, inter alia, by: due to a significantly reduced water absorption and solvent absorption as well as a significantly reduced washout loss. The shaped bodies obtained with the aid of the binders according to the invention include high strength. The method according to the invention for producing the thermally curable binders is simple and economical to carry out.

Examples

The following non-limiting examples illustrate the invention.

example 1

A) Preparation of the acid polymer SP

0.55 kg of fully demineralized water, 0.36 kg of maleic anhydride and 0.91 kg of a 40% strength by weight aqueous solution of an ethoxylated oleylamine (average degree of ethoxylation = 12, from BASF AG) are placed in a pressure reactor with anchor stirrer. The mixture is heated to 125 ° C. under a nitrogen atmosphere. After this temperature has been reached, feed 1 consisting of

0.75 kg of fully demineralized water and 1.00 kg of acrylic acid as well as within 2 hours of feed 2, consisting of 0.22 kg of fully demineralized water water and 0.12 kg H ₂ 0 ₂ (30 wt .-%) evenly metered. At the end of feed 1, a further 0.11 kg of fully demineralized water are added. After the reaction is cooled to room temperature. The aqueous polymer solution thus obtained has a solids content of 43.2%, a pH of 1.7 and a viscosity of 450 mPas. The K value is 13.3.

B) polymer dispersions

(Emulsion polymerization in the presence of the acid polymer)

10

Polymer dispersion with EP1:

640 g of water and 133.1 g of an aqueous solution of the acid polymer SP are placed in a 4 1 glass vessel with an anchor stirrer (120 rpm)

15 (43.2 wt .-%) from Example A and 5.35 g (10%) of feed 2 and heated to 90 ° C. After 10 minutes, the remainder of feed 1 are metered in spatially separately within 3 h and the remaining amount of feed 2 within 3.5 h at this temperature. Subsequently, a further 30 minutes at this temperature

20 polymerized and the reaction mixture cooled and mixed with feed 3. The polymer dispersion prepared in this way contains 47.3% by weight of nonvolatile components and has a pH of 2.7. The viscosity of the polymer dispersion obtained is 630 mPas (at 250 s ^_1 ). Finally, the dispersion is mixed with

25 9 parts by weight of triethanolamine (based on the solids content).

Feed 1: 185.32 g water 665.51 g SP (43.2%) 30 805.00 g styrene (100%) 287.50 g MMA (100%) 57.50 g HEA (100%)

Feed 2 35 619 g of deionized water 3.45 g of sodium peroxodisulfate

Feed 3 1863.43 g SP (43.2%) 40% by weight triethanolamine and / or epoxy compound

(according to tables I to V)

(Triethanolamine and epoxy compound are added at different times)

45 Here mean:

MMA: Methyl methacrylate HEA: Hydroxyethy1acry1at C) Determination of water absorption (WA) and wash-out losses (AV) with water

The polymer films obtained from B) without or with additives (TEA: triethanolamine; E: Epicote® 828, bisphenol A diglycidyl ether) were dried at room temperature for 3 days, then dried at 50 ° C. for a further 3 days.

To determine the water absorption (WA) and the washout losses (AV), approx. 0.2 to 0.3 g polymer film was stored in 10 g water for 24 hours.

The polymer film (Acrodur® D100 from BASF Aktiengesellschaft) consisted of 100 parts by weight of SP (from acrylic acid and maleic anhydride; obtained in section A) and 70 parts by weight of styrene, 25 parts by weight of methyl methacrylate and 5 parts by weight Hydroxyethyl acrylate (obtained in Section B).

The results of Example 1 are shown in Table I below.

Table I

WA and AV after annealing the polymer film at 80 ° C for 30 min

WA and AV after annealing the polymer film at 130 ° C for 30 min

Beispiel 2

Example 2

The same acid polymer (SP) as in Example 1 was used. The emulsion polymerization was carried out analogously to section B of Example 1 in the presence of the SP with 73.5 parts by weight of ethylhexyl acrylate, 21 parts by weight of styrene and 5.5 parts by weight of hydroxyethyl acrylate.

The polymer films obtained in this way with or without additives (TEA: triethanolamine; E: Epicote® 828, bisphenol A diglycidyl ether) were first dried at room temperature for 3 days and then at 50 ° C. for 3 more days ,

To determine the water intake (WA) and the washout losses (AV), about 0.2 to 0.3 g of polymer film were stored in 10 g of water or in 100 g of acetone for 24 hours.

The polymer film consisted of 100 parts by weight of SP (from acrylic acid and maleic anhydride, obtained in section A) and 73.5 parts by weight of ethylhexyl acrylate, 21 parts by weight of styrene and 5.5 parts by weight of hydroxyethyl acrylate.

The results of Example 2 are shown in Table II below.

Table II

WA and AV without tempering

WA und AV nach Tempern des Polymerfilms bei 100°C für 30 min

WA and AV after annealing the polymer film at 100 ° C for 30 min

WA and AV after annealing the polymer film at 150 ° C for 30 min

Example 3

The same acid polymer (SP) and the same emulsion polymer (EP) as in Example 2 were used in the monomer composition.

The polymer films obtained in this way without or with additives (TEA: triethanolamine or the epoxy compounds listed in Table III) were first at room temperature for 3 days, then at 50 ° C. for a further 3 days and optionally for a further 30 minutes 100 ° C or annealed at 150 ° C.

To determine the solvent uptake (LA) or the washout losses (AV) in THF (tetrahydrofuran), about 0.5 g of the polymer film was stored in 90 ml of THF for 24 hours. For the AV value, the polymer films were predried for 7 days at room temperature and then further dried at 50 ° C. in a forced air oven to constant weight.

The results of Example 3 are shown in Table III below. Table III

AV without tempering

AV after tempering at 150 ° C

Solvent absorption (LA) from THF

Example 4

The polymer dispersion obtained in Example 1 was tested for sand specimens with regard to their flexural strength (BF) and water absorption (WA). The flexural strength [N / mm ² ] was determined after 3 hours of water storage at 80 ° C. At the same time, the water absorption of the sand test specimens was measured. This was done using the following method:

300 g of quartz sand H34 were mixed with the binder compositions at room temperature (5% by weight or 3% by weight of dry binder according to the table, based on sand). Test specimens (Fischer bars) with the dimensions 17 x 2.3 x 2.3 cm are formed from the moist mixtures in a corresponding metal mold, compressed and cured after demolding for 2 hours in a convection oven at temperatures according to the table. A PRA ram from Georg Fischer AG is used for compaction. The bars were stored in 80 ° C warm water for 3 hours before testing. Then the water absorption of the still wet bars was determined (in table WA after WL).

The flexural strength (BF) of the Fischer bars produced in this way is determined in dry condition at 23 ° C specimen temperature in a type PFG strength tester with the PBV test device (Georg Fischer, Schaffhausen / CH) (in Table BF according to WL).

The results of the tests are shown in Table IV below. Table IV

Curing temperature 150 ° C for 2 hours

Curing temperature 170 ° C for 2 hours

Here mean:

TEA: Triethano1ami E: Epicote® 828 (bisphenol A diglycidyl ether)

Example 5

The polymer dispersions obtained in Examples 1 and 2 were subjected to the following boiling test with regard to their suitability as a binder for cork granules:

92.5% by weight of cork, coarse, 7.5% by weight of binder; Cook test after 3 hours; Press duration 2 hours.

In a Kenwood laboratory mixer, 100 g of dried cork granulate (cleaned and ground cork, average particle size approx. 8 mm) and 15 g of 50% binder from the examples given are mixed for 2 minutes. The cork particles loaded with binder are pressed without further drying in a two-part metal mold at a pressing temperature of 80 ° C to 100 ° C for 2 h at a pressure of 100 bar. The metal mold has an internal dimension of 15 x 15 mm, the bottom and stamp of the mold for removing the released water vapor being perforated with ventilation holes.

Test specimens measuring 5 x 5 x 3 cm are cut from these rigid cork blocks and their swelling in thickness is tested under the test conditions specified above.

The results of the cooking test of cork blocks are shown in Table V for the polymer dispersion from Example 1 and in Table VI for the polymer dispersion from Example 2.

Table V

Table VI

Here mean:

TEA: triethanolamine

E: Epicote® 828 (bisphenol A diglycidyl ether)

Claims

claims 1. A thermally curable binder based on an aqueous polymer dispersion an emulsion polymer (EP for short), a polymer which is composed of at least 5% by weight of an ethylenically unsaturated monocarboxylic acid, dicarboxylic acid or dicarboxylic acid anhydride (acid polymer SP for short) and mono- or multifunctional epoxy compounds as hardeners. 2. Thermally curable binder according to claim 1, wherein the mono- or multifunctional epoxy compound is used in the liquid state as a hardener. 3. Thermally curable binder according to claims 1 or 2, wherein a di- or a trifunctional epoxy compound as Harder is used. 4. Thermally curable binder according to claims 1 to 3, wherein the emulsion polymer (EP) to at least 40 wt .-% of so-called main monomers selected from Ci bis C ₂ o-alkyl (meth) acrylates, vinyl esters of carboxylic acids containing up to 20 C atoms, vinyl aromatics with up to 20 C atoms, ethylenically unsaturated nitriles, vinyl halides, vinyl ethers of alcohols containing 1 to 10 C atoms, aliphatic Hydrocarbons with 2 to 8 carbon atoms and one or two double bonds or mixtures of these monomers is built up. 5. Thermally curable binder according to claims 1 to 4, wherein the acid polymer (SP) is composed of 50 to 99.5% by weight of at least one ethylenically unsaturated mono- or dicarboxylic acid of a dicarboxylic acid anhydride or mixtures thereof, 0.5 to 50% by weight of at least one ethylenically unsaturated compound which is selected from the esters of ethylenically unsaturated monocarboxylic acids and the half-esters and diesters of ethylenically unsaturated dicarboxylic acids with an amine having at least one hydroxyl group and optionally up to 20% by weight of at least one further monomer. 6. Thermally curable binder according to claims 1 to 5, 5 wherein the weight ratio of the emulsion polymer (EP) to the acid polymer (SP), on a solid basis, is in the range from 7: 1 to 1: 7. 7. Thermally curable binder according to claims 1 to 6, 10 wherein the aqueous polymer dispersion additionally as a hardener Contains polyol or an alkanolamine with at least two hydroxyl groups. 8. A process for the preparation of thermally curable binders according to claims 1 to 7, based on an aqueous polymer dispersion, characterized in that first the monomers forming the emulsion polymer are polymerized in the presence of the acid polymer and in the dispersion obtained in this way then mono- or 20 multifunctional epoxy compounds are stirred in. 9. A process for the preparation of thermally curable binders according to claims 1 to 7, based on an aqueous polymer dispersion, characterized in that 25 during the polymerization of the monomers forming the emulsion polymer and in the presence of the acid polymer, the mono- or multifunctional epoxy compounds are stirred in. 10. The method according to claims 8 or 9, wherein the stirring of the mono- or multifunctional epoxy compounds takes place at temperatures from 10 to 100 ° C. 11. Use of the thermally curable binder according to Claims 35 to 7, based on a polymer dispersion as Binder for molded articles or nonwovens made of fibrous or granular materials. 40 5